I am trying to put my 06 crew back together and I do not have any screws bolts or push pins to hold down the core support cover. This is the cover with the fan diagram and such. It looke to have about 10 holes in it for Either push ins or bolts?

 

Mine has the plastic rivets. I took mine off and ended up having to buy a handful of new rivets. I found them at Lowe's in the loose nuts and bolts section. They carry many of the plastic rivet related parts that are specific to Ford and GM (and maybe even other makes) .